Accumulator

ABSTRACT

An accumulator according to an embodiment includes, for example, a base member; a cover member welded to the base member, the cover member and the base member defining a pressure chamber therebetween; a stretchable partition member that partitions the pressure chamber into an inner chamber and an outer chamber; and a labyrinth structure provided in at least one of a first part of the base member and a second part of the cover member. The first part is located closer to the outer chamber than a welded part between the base member and the cover member. The second part is located closer to the outer chamber than the welded part, facing the first part.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is national stage application of InternationalApplication No. PCT/JP2016/071187, filed Jul. 19, 2016, which designatesthe United States, incorporated herein by reference, and which is basedupon and claims the benefit of priority from Japanese Patent ApplicationNo. 2015-164222, filed Aug. 21, 2015, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

This disclosure generally relates to an accumulator.

BACKGROUND ART

Conventionally, accumulators including a pressure chamber defined by twomembers joined by full-circled welding are known (see Patent Literature1). Patent Literature 1 describes a welded part covered by a ring inorder to prevent entry of sputter into the pressure chamber duringwelding.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Application Laid-open No.2005-351297

SUMMARY OF INVENTION Problem to be Solved by the Invention

By inclusion of the ring, the above conventional accumulator increasesin the number of parts, for example.

It is thus a problem to be solved of the present invention to attain anaccumulator that can be less affected by sputter without using aseparate member, for example.

Means for Solving Problem

An accumulator according to an embodiment of the present inventionincludes, for example, a base member; a cover member that is welded tothe base member, the cover member and the base member defining apressure chamber therebetween; a partition member that is stretchableand partitions the pressure chamber into an inner chamber and an outerchamber; and a labyrinth structure provided in at least one of a firstpart of the base member and a second part of the cover member, the firstpart being located closer to the outer chamber than a welded partbetween the base member and the cover member, the second part beinglocated closer to the outer chamber than the welded part, the secondpart facing the first part.

The accumulator includes the labyrinth structure in at least one of thefirst part and the second part located on the outer chamber side of thewelded part. According to the accumulator, for example, it is possibleto prevent sputter occurring from welding of the welded part from movingtoward the outer chamber and affecting the partition member or causingdust in the outer chamber.

In the accumulator, the labyrinth structure is provided between thewelded part and the partition member. According to the accumulator, forexample, it is possible to prevent the sputter occurring from welding ofthe welded part from affecting the partition member.

In the accumulator, the labyrinth structure includes a wall provided inone of the first part and the second part, the wall that projectstowards the other of the first part and the second part. According tothe accumulator, for example, the labyrinth structure having arelatively simple structure is attainable.

In the accumulator, the wall contacts with the other of the first partand the second part. According to the accumulator, for example, sincethe gap between the first part and the second part is narrowed, it ispossible to more certainly prevent the sputter occurring from welding ofthe welded part and the dust caused by the sputter from moving towardthe outer chamber.

In the accumulator, a radial thickness of the wall decreases toward theother of the first part and the second part. According to theaccumulator, by an increased contact pressure between the first part andthe second part, the gap between the first part and the second part canbe easily occluded. Thus, for example, the sputter occurring fromwelding of the welded part and the dust caused by the sputter can bemore certainly prevented from moving toward the outer chamber.

In the accumulator, the labyrinth structure covers the welded part.According to the accumulator, for example, it is possible to preventsputter occurring from welding of the welded part from moving toward theouter chamber and affecting the partition member or causing dust in theouter chamber in the outer chamber.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exemplary and schematic sectional view of an accumulatoraccording to a first embodiment;

FIG. 2 is an enlarged view of a part A in FIG. 1;

FIG. 3 is an enlarged view of a part of an accumulator according to afirst modification of the first embodiment, at a position equivalent tothe position of the part A in FIG. 1;

FIG. 4 is an enlarged view of a part of an accumulator according to asecond modification of the first embodiment, at a position equivalent tothe position of the part A in FIG. 1;

FIG. 5 is an enlarged view of a part of an accumulator according to athird modification of the first embodiment, at a position equivalent tothe position of the part A in FIG. 1;

FIG. 6 is an enlarged view of a part of an accumulator according to afourth modification of the first embodiment, at a position equivalent tothe position of the part A in FIG. 1; and

FIG. 7 is an exemplary and schematic sectional view of an accumulatoraccording to a second embodiment.

DESCRIPTION OF EMBODIMENTS

Hereinafter, exemplary embodiments of the present invention aredisclosed. Constitutions of the embodiments illustrated below andoperation and results (effects) derived from the constitutions aremerely exemplary. The present invention can also be achieved by aconstitution other than the constitutions disclosed in the followingembodiments. Furthermore, the present invention can achieve at least oneof various advantageous effects (also including derivative effects)attained by the constitutions.

The following embodiments and modifications include same or likeconstitutional elements. Hereinafter, the same or like constitutionalelements are given the same numerals codes, and their repeatedexplanations may be omitted. In the present description, ordinal numbersare assigned to differentiate components or parts for the sake ofconvenience and are not intended to indicate priority or order.

First Embodiment

FIG. 1 is a sectional view of an accumulator 1. The accumulator 1includes a base member 2 and a cover member 3. The cover member 3 has acylindrical shape having one open end and the other closed end. That is,the cover member 3 includes a tubular part 3 a and a bottom wall 3 b.The base member 2 has a disc-like shape, and covers one end, that is,the open end of the cover member 3. The outer peripheries of the basemember 2 and the cover member 3 are joined to each other by full-circledwelding. The base member 2 and the cover member 3 are joined to eachother by electron beam welding or resistance welding, for example,however, welding type and method are not limited to these examples. Eachof the base member 2 and the cover member 3 is formed of a metallicmaterial such as stainless steel, however, the material thereof is notlimited thereto. The base member 2 may also be referred to as a lidmember. The cover member 3 may also be referred to as a shell. Thetubular part 3 a may also be referred to as a peripheral wall or a sidewall. The bottom wall 3 b may also be referred to as an end wall.

The base member 2 and the cover member 3 define a pressure chamber R.The pressure chamber R accommodates a partition member 4 joined to theinner surface of the base member 2. The partition member 4 has acylindrical shape having one open end and the other closed end. That is,the partition member 4 includes a tubular part 4 a and a bottom wall 4b. The base member 2 covers one end, that is, the open end of thepartition member 4. The outer peripheries of the base member 2 and thepartition member 4 are joined to each other by full-circled welding. Thepartition member 4 is housed in the pressure chamber R, partitioning thepressure chamber R into an inner chamber Ri and an outer chamber Ro.

The tubular part 4 a is an axially stretchable metallic bellows. Thebottom wall 4 b has a disc-like shape. The outer peripheries of thetubular part 4 a and the bottom wall 4 b are joined to each other byfull-circled welding. Each of the tubular part 4 a and the bottom wall 4b is formed of a metallic material such as stainless steel, however, thematerial thereof is not limited to a metallic material. The tubular part4 a may also be referred to as an elastic part. The bottom wall 4 b mayalso be referred to as an end wall.

An auxiliary tube 5 is joined to the pressure chamber-R side of the basemember 2 inside the inner chamber Ri. The auxiliary tube 5 has acylindrical shape having one open end and the other closed end. That is,the auxiliary tube 5 has a tubular part 5 a and a bottom wall 5 b. Thebase member 2 covers one end, that is, the open end of the auxiliarytube 5. The outer peripheries of the base member 2 and the auxiliarytube 5 are joined to each other by full-circled welding. The tubularpart 5 a may be referred to as a peripheral wall or a side wall. Thebottom wall 5 b may also be referred to as an end wall. The auxiliarytube 5 is formed of a metallic material such as stainless steel, forexample, however, the material thereof is not limited to this example.

The auxiliary tube 5 partitions the inner chamber Ri into a main chamberRim and an auxiliary chamber Ris. The bottom wall 5 b is provided with acommunicating hole 5 c that connects the main chamber Rim and theauxiliary chamber Ris.

The accumulator 1 according to the present embodiment is of so-called anexternal gas accumulation. That is, the outer chamber Ro stores a gastherein, and the inner chamber Ri (main chamber Rim and auxiliarychamber Ris) stores a liquid therein. The inner chamber Ri can store aliquid while the tubular part 4 a of the partition member 4 is beingstretched. The outer chamber Ro can also store a liquid for adjustingthe volume of the gas.

The base member 2 is provided with a liquid passage 2 a which faces theauxiliary chamber Ris. The liquid flows through the liquid passage 2 abetween the auxiliary chamber Ris and the outside of the accumulator 1.The liquid also flows through the communicating hole 5 c between theauxiliary chamber Ris and the main chamber Rim.

A sealing member 6 is attached to the communicating hole-5 c side of thebottom wall 4 b of the partition member 4. In the most shrunk state ofthe partition member 4, the sealing member 6 closes the communicatinghole 5 c from the main chamber-Rim side. The partition member 4 isshrinkable to the position where the sealing member 6 contacts with theauxiliary tube 5. That is, in the present embodiment, the auxiliary tube5 sets a shrink range of the partition member 4, and prevents thepartition member 4 from excessively shrinking. Furthermore, the sealingmember 6 can buffer impact from the direct contact between the bottomwall 4 b of the partition member 4 and the bottom wall 5 b of theauxiliary tube 5. That is, the sealing member 6 is also one example of abuffer member. The sealing member 6 can be made from an elasticmaterial, such as a synthetic resin material or an elastomer.

A short annular cylindrical guide member 7 is attached to the outerchamber-Ro side of the bottom wall 4 b of the partition member 4. Theguide member 7 slides along the inner surface of the tubular part 3 a ofthe cover member 3 together with the stretching/shrinking of thepartition member 4. The guide member 7 guides the partition member 4 toprevent the partition member 4 from inclining, bending, or vibrating.Thus, the guide member 7 may also be referred to as a damping member.Furthermore, the guide member 7 prevents the direct contact between thepartition member 4 and the inner peripheral face of the cover member 3.Thus, the guide member 7 may also be referred to as an anti-wear member.The guide member 7 can be made of a synthetic resin material, forexample.

The guide member 7 is provided with a passage (not illustrated in thedrawings), such as a recess or a gap, in the outer edge. The gas and thegas-volume adjusting liquid stored in the outer chamber Ro can flow backand forth through the passage between both sides of the guide member 7in the outer chamber Ro, that is, between the outer peripheral area ofthe tubular part 4 a and the axially outer area of the bottom wall 4 bin the outer chamber Ro.

The gas is enclosed in the outer chamber Ro. The cover member 3 isprovided with a gas inlet 3 c in the bottom wall 3 b. The outer chamberRo is filled with the gas supplied from outside through the gas inlet 3c and thereafter, the gas inlet 3 c is closed by a plug 8.

The liquid passage 2 a is connected to, for example, a hydraulic circuitof a braking device. In stretched state of the partition member 4, theliquid is introduced and stored into the inner chamber Ri from thehydraulic circuit. In shrunk state of the partition member 4, the liquidis returned from the inner chamber Ri to the hydraulic circuit.

FIG. 2 is an enlarged view of a part A in FIG. 1. As illustrated in FIG.2, in the present embodiment a labyrinth structure 20 is disposed on theouter chamber-Ro side of a first welded part W1 between the base member2 and the cover member 3 so as to cover the first welded part W1. Thatis, the labyrinth structure 20 is disposed between the first welded partW1 and the tubular part 4 a of the partition member 4, or between thefirst welded part W1 and a second welded part W2 between the base member2 and the partition member 4. The first welded part W1 is one example ofa welded part.

The labyrinth structure 20 in the present embodiment is provided to eachof a first part 2 b of the base member 2 and a second part 3 d of thecover member 3. The first part 2 b is a part of the outer peripheral endof the base member 2 and is closer to the outer chamber Ro than thefirst welded part W1. The second part 3 d is a part of the open end ofthe tubular part 3 a of the cover member 3 and is closer to the outerchamber Ro than the first welded part W1. The first part 2 b and thesecond part 3 d face each other with a gap in the peripheral edge of theouter chamber Ro. The labyrinth structure 20 can prevent sputteroccurring from welding of the first welded part W1 from moving towardthe outer chamber Ro, thereby preventing the sputter from adhering tothe tubular part 4 a of the partition member 4 or causing dust in theouter chamber Ro.

To be more specific, the first part 2 b is stepwise, and has a firstperipheral face 21 a, a first annular face 21 b, a second peripheralface 21 c, and a second annular face 21 d in order from the first weldedpart-W1 side. The first peripheral face 21 a and the first annular face21 b define a first annular corner 22 a. The second peripheral face 21 cand the second annular face 21 d define a second annular corner 22 b.The first corner 22 a and the second corner 22 b are one example of awall of the first part 2 b, the wall projecting toward the second part 3d. The first corner 22 a and the second corner 22 b may also be referredto as projections.

The second part 3 d is also stepwise, and has a first inner peripheralface 31 a, a third annular face 31 b, and a second inner peripheral face31 c in order from the first welded part W1 side. The third annular face31 b and the second inner peripheral face 31 c define a third annularcorner 32 a. The third corner 32 a is one example of a wall of thesecond part 3 d, the wall projecting towards the first part 2 b. Thethird corner 32 a may also be referred to as a projection.

The third corner 32 a enters a recess (corner) between the first corner22 a and the second corner 22 b. That is, the first corner 22 a, thethird corner 32 a, and the second corner 22 b are alternately arrangedto fit in with each other with a gap, covering the first welded part W1.Thus, in the present embodiment, mutually overlapping corners of thelabyrinth structure 20, that is, the first corner 22 a, the third corner32 a, and the second corner 22 b form a gap that extends in bent form asaway from the first welded part W1. The first corner 22 a, the secondcorner 22 b, and the third corner 32 a can independently serve as thelabyrinth structure 20 and prevent the movement of the sputter.

In the present embodiment, the first part 2 b includes, in the firstcorner 22 a, an annular projection 23 that projects from the firstannular face 21 b. The distal end of the projection 23 contacts with thethird annular face 31 b of the second part 3 d. This narrows the gapbetween the first part 2 b and the second part 3 d, thereby morecertainly preventing the sputter occurring from welding of the firstwelded part W1 and the dust caused by the sputter from moving toward theouter chamber Ro. The distal end of the projection 23 may be elasticallyor plastically deformed at the time of joining the base member 2 and thecover member 3 to each other. The periphery of the projection 23 doesnot entirely contact with the second part 3 d, and is separated with agap from the second part 3 d at least one or two or more locations, forexample. That is, in the outer chamber Ro, a part on the first weldedpart-W1 side of the projection 23 is communicated with a part on theopposite side. This can prevent the formation of a closed space on thefirst welded part-W1 side of the projection 23 and prevent the closedspace from excessively rising in pressure when heated at the time ofwelding of the first welded part W1. The projection 23 is one example ofa wall.

As explained heretofore, according to the present embodiment, the firstpart 2 b and the second part 3 d, which are located on the outerchamber-Ro side, i.e., pressure chamber-R side of the first welded partW1, includes the labyrinth structure 20. Thereby, the present embodimentcan prevent, for example, the sputter occurring from welding of thefirst welded part W1 from moving toward the outer chamber Ro andaffecting the partition member 4, e.g., adhering to the tubular part 4a, or causing dust in the outer chamber Ro.

In the present embodiment, the labyrinth structure 20 is providedbetween the first welded part W1 and the tubular part 4 a (metallicbellows) of the partition member 4. According to the present embodiment,thus, the sputter caused by the welding of the first welded part W1 canbe more certainly prevented from affecting the partition member 4, forexample.

In the present embodiment, the labyrinth structure 20 further has thefirst corner 22 a, the third corner 32 a, and the second corner 22 b(wall). According to the present embodiment, the labyrinth structure 20with a relatively simple structure is thus attainable.

In the present embodiment, the projection 23 projecting from the firstcorner 22 a of the first part 2 b contacts with the second part 3 d. Dueto the narrowed gap between the first part 2 b and the second part 3 d,the present embodiment can more certainly prevent the sputter occurringfrom welding of the first welded part W1 and the dust caused by thesputter from moving toward the outer chamber Ro, for example.

In the present embodiment, the labyrinth structure 20 is provided tocover the first welded part W1. According to the present embodiment, thesputter caused by welding of the first welded part W1 can be morecertainly prevented from moving toward the outer chamber Ro, forexample.

First Modification

An accumulator 1A of the present modification illustrated in FIG. 3 alsohas the same structure as that of the accumulator 1 of theabove-mentioned embodiment. Thus, the present modification can alsoattain the same effects (results) based on the same structure. However,the present modification differs in that the first annular face 21 b hasa conical concave shape, and the first corner 22 a projects towards thethird annular face 31 b as a whole. The distal end of the first corner22 a serves as the projection 23 which contacts with the third annularface 31 b. According to the present modification, for example, it ispossible to form the projection 23 having a relatively simple structure.The projection 23 is also sharp in form which decreases in radialthickness toward the second part 3 d, and exerts higher contact pressurethan the projection 23 of not sharp form. Because of this, the distalend of the projection 23 or the third annular face 31 b is easilydeformable. That is, the gap between the first part 2 b and the secondpart 3 d can be easily occluded. This can lead to more certainlypreventing the sputter occurring from welding of the first welded partW1 and the dust caused by the sputter from moving toward the outerchamber Ro, for example.

Second Modification

An accumulator 1B of the present modification illustrated in FIG. 4 alsohas the same structure as that of the accumulator 1 of theabove-mentioned embodiment. The present modification can also attain thesame effects (results) based on the same structure. However, the presentmodification differs in that a projection 33 projects from the thirdannular face 31 b of the second part 3 d and contacts with the firstannular face 21 b of the first part 2 b. That is, the projection 33 maybe provided in the second part 3 d. The projection 33 is one example ofa wall.

Third Modification

An accumulator 1C of the present modification illustrated in FIG. 5 alsohas the same structure as that of the accumulator 1 of theabove-mentioned embodiment. The present modification can also attain thesame effects (results) based on the same structure. However, the presentmodification differs in that the third annular face 31 b of the secondpart 3 d, which contacts the projection 23 of the first part 2 b, has aconical convex shape. In this case, the contact pressure between theprojection 23 and the third annular face 31 b can further increase bythe contact between the corner of the projection 23 and the thirdannular face 31 b, making the distal end of the projection 23 or thethird annular face 31 b easily deformable. Thus, the gap between thefirst part 2 b and the second part 3 d can be easily occluded. Accordingto the present modification, it is made more difficult, for example, forthe sputter occurring from welding of the first welded part W1 and thedust caused by the sputter to pass the contact portion between theprojection 23 and the third annular face 31 b.

Fourth Modification

An accumulator 1D of the present modification illustrated in FIG. 6 alsohas the same structure as that of the accumulator 1 of theabove-mentioned embodiment. Thus, the present modification can alsoattain the same effects (results) based on the same structure. However,the present modification differs in that the first annular face 21 b hasa conical concave shape, the third annular face 31 b has a conicalconvex shape, and the first annular face 21 b and the third annular face31 b face each other with a narrow gap. In such structure, setting arelatively narrow gap between the first annular face 21 b and the thirdannular face 31 b makes it difficult for the sputter occurring fromwelding of the first welded part W1 and the dust caused by the sputterto move toward the outer chamber Ro.

Second Embodiment

An accumulator 1E of the present embodiment illustrated in FIG. 7 alsohas the same structure as those of the accumulators 1 to 1D in the firstembodiment and the modifications. Thus, the present embodiment can alsoattain the same effects (results) based on the same structure. However,the accumulators 1 to 1D in the first embodiment and modificationsillustrated in FIGS. 1 to 6 are of so-called external gas accumulationenclosing a gas outside a partition member 4E, that is, outside atubular part 4 a (metallic bellows), and having a liquid introduced intothe inside of the partition member 4E. The accumulator 1E of the presentembodiment is, however, of so-called an internal gas accumulationenclosing a gas inside the partition member 4E, that is, inside thetubular part 4 a (metallic bellows), and having a liquid introduced intothe outside of the partition member 4E.

A cover member 3E has a cylindrical shape having one closed end and theother open end. That is, the cover member 3E has a tubular part 3 a anda bottom wall 3 f. A base member 2E has a disc-like shape, and coversthe open end, that is, the other end of the cover member 3E. The covermember 3E and the base member 2E are joined to each other at a firstwelded part W1 by full-circled welding. The cover member 3E is providedwith a liquid passage 3 g.

The partition member 4E defines, inside, an inner chamber Ri enclosing agas and defines, outside, an outer chamber Ro into which a liquid isintroduced. The partition member 4E is stretchable to the position wherea sealing member 6 on the bottom wall-3 f side of a bottom wall 4 bcontacts with the bottom wall 3 f. In the most stretched state of thepartition member 4E, the sealing member 6 occludes the liquid passage 3g. There is a gap provided between the outer periphery of the guidemember 7 and the inner peripheral face of the tubular part 3 a. Thus,the surroundings of the tubular part 4 a of the partition member 4E arealso a part of the outer chamber Ro.

The internal gas-accumulation accumulator 1E of the present embodimentmay also include a labyrinth structure 20, for the first welded part W1,similar to those of the first embodiment and the modifications. Thelabyrinth structure 20 of the present embodiment is provided to each ofa first part 2 c of the base member 2E and a second part 3 e of thecover member 3E. The first part 2 c is a part of the outer peripheralend of the base member 2E and is closer to the outer chamber Ro than thefirst welded part W1. The second part 3 e is a part of the axial end ofthe tubular part 3 a of the cover member 3E and is closer to the outerchamber Ro than the first welded part W1. The first part 2 c and thesecond part 3 e face each other with a gap in the peripheral edge of theouter chamber Ro. In the present embodiment, the labyrinth structure 20can prevent the sputter occurring from welding of the first welded partW1 from moving toward the outer chamber Ro and adhering to the tubularpart 4 a of the partition member 4E or causing dust in the outer chamberRo.

The embodiments of the present invention have been illustrated as above,however, the aforementioned embodiments are merely exemplary and notintended to limit the scope of the invention. The above embodiments maybe implemented in other various modes. Without departing from the spiritof the invention, various omissions, replacements, combinations, andchanges may be made. Specifications (structure, kind, number, size,position, arrangement, and the like) of each element, mechanism, andform may be appropriately modified for implementation. Theabove-mentioned embodiments and modifications can be partiallyinterchanged structurally. For example, it is not necessary to providethe partition member on the base member to be welded to the covermember. The accumulators can be applied to devices in various fields.

EXPLANATIONS OF LETTERS OR NUMERALS

-   -   1, 1A to 1E Accumulator    -   2, 2E Base member    -   2 b, 2 c First part    -   3, 3E Cover member    -   3 d, 3 e Second part    -   4, 4E Partition member    -   20 Labyrinth structure    -   22 a First corner (wall)    -   22 b Second corner (wall)    -   23 Projection (wall)    -   32 a Third corner (wall)    -   33 Projection (wall)    -   R Pressure chamber    -   Ri Inner chamber    -   Ro Outer chamber    -   W1 First welded part (welded part)

1. An accumulator comprising: a base member; a cover member that iswelded to the base member, the cover member and the base member defininga pressure chamber therebetween; a partition member that is stretchableand partitions the pressure chamber into an inner chamber and an outerchamber; and a labyrinth structure provided in at least one of a firstpart of the base member and a second part of the cover member, the firstpart being located closer to the outer chamber than a welded partbetween the base member and the cover member, the second part beinglocated closer to the outer chamber than the welded part, the secondpart facing the first part.
 2. The accumulator according to claim 1,wherein the labyrinth structure is provided between the welded part andthe partition member.
 3. The accumulator according to claim 1, whereinthe labyrinth structure includes a wall provided in one of the firstpart and the second part, the wall that projects towards the other ofthe first part and the second part.
 4. The accumulator according toclaim 3, wherein the wall contacts with the other of the first part andthe second part.
 5. The accumulator according to claim 4, wherein aradial thickness of the wall decreases toward the other of the firstpart and the second part.
 6. The accumulator according to claim 1,wherein the labyrinth structure covers the welded part.